Type “message” into the App store and you get nearly 8,000 results – and the numbers using of the main messaging apps, such as the Facebook-owned WhatsApp and WeChat, have escalated into hundreds of millions of people, sending billions of messages, in recent years.

And it is partly because of this that tracking the actions and intentions of jihadi extremists is becoming more difficult.

A regular feature of Islamic State accounts on Twitter is other ways in which they can be contacted via messaging apps and social media websites (see picture, below).

Kik is one app that regularly features on jihadi profiles. The instant messaging app, which has around 120 million users – mostly teenagers in the US – has previously been in the papers because of its problems with porn bots, automated disseminators of hardcore pornography.

But aside from graphic spam and hardcore porn, hardcore jihadists are also lurking within Kik.

‘Emotional bond’

Start (the National Consortium for the Study of terrorism and Responses to Terrorism) says people use Kik and other apps for real time communication with fighters in the field about recruitment and travel to areas like the Islamic State.

The Ask.fm social media site, which allows users to anonymously ask questions to a public profile, means jihadis can communicate with potential recruits through their answers. Start says this creates a “familiarity or emotional bond” between potential jihadis and fighters – increasing the chances of radicalisation.

The report said: “Most people in the UK now use many different methods of communication. There are fixed line voice calls, mobile voice calls, SMS messages, voice/video/email messages over internet services such as Skype, Gmail and Facebook, and conversations using huge numbers of smartphone applications (for example, Whatsapp, BlackBerry Messenger and Instagram).”

But there is another level of secrecy jihadis add to their online activities. Islamic State online accounts regularly pass around information, often via content sharing websites, on how to further conceal their online footprint.

“The United States government, the government of the United Kingdom, France, and elsewhere, want to jail you. They want you to suffer. And they aren’t playing games,” one such advice document seen by Channel 4 News states.

Advice includes using setting up VPNs (virtual private networks, which hide data from websites such as IP addresses), encrypting email and making sure social media conversations are secure.

David Cameron told parliament on Tuesday that “terrorists are using the internet to communicate with each other and we must not accept that these communications are beyond the reach of the authorities or the internet companies themselves.”

Perhaps the conversations on platforms other than just Facebook are not entirely beyond the authorities’ reach – but it is getting more and more difficult to say that with confidence in the era of digitally-savvy jihad.